1. Field of the Invention
This invention relates to a drive device, a lens barrel and a camera, and more particularly to a drive device arranged to transmit rotation of a rotation shaft of a motor to a gear or the like and to drive a lens in the direction of an optical axis by using the gear.
2. Description of the Related Art
Rotation amount detecting means for detecting the amount of rotation of the output shaft of a motor or that of a gear connected to the output shaft has been arranged to include a pulse disc (rotary scale) and an optical sensor, such as a photo-interrupter or a photo-reflector, which is arranged to detect the rotation of the pulse disc. The lead wires of the optical sensor and the lead wires of the motor which is a drive source are connected to a flexible printed circuit board to form a motor drive unit.
In incorporating the motor drive unit into a lens barrel, the flexible printed circuit board is electrically connected to a printed circuit board having a lens control circuit arranged within the lens barrel.
However, since the flexible printed circuit board is expensive, the use of it has hindered an attempt to reduce the cost of the product.
Further, in cases where an electric element is included in the motor drive unit, it is necessary to join, by soldering, the electric element to the flexible printed circuit board after assembly work on the motor drive unit.
In soldering, however, the solder tends to spatter around and stick to gears or the like within the motor drive unit to cause inadequate rotation. To prevent spattering of the solder in soldering, it is necessary to have masking. However, the necessity of masking has presented another problem as it causes a great disadvantage in respect to cost of assembly.